WO2007086220A1

WO2007086220A1 - Cata-dioptric imaging system, exposure device, and device manufacturing method

Info

Publication number: WO2007086220A1
Application number: PCT/JP2006/325711
Authority: WO
Inventors: Yasuhiro Omura
Original assignee: Nikon Corporation
Priority date: 2006-01-30
Filing date: 2006-12-25
Publication date: 2007-08-02
Also published as: US7990609B2; JPWO2007086220A1; EP1980890A1; EP1980890A4; EP1980890B1; US20090027768A1; KR20080091182A

Abstract

Provided is a cata-dioptric imaging system of a highly numerical aperture, which has its various aberrations satisfactorily corrected by using neither a reflecting surface having an aspherical shape of a high order nor a reciprocal optical element. The cata-dioptric imaging system forms the image of a first plane (R) on a second plane (W), and is constituted to include a first focusing system (G1) for forming a first intermediate image of the first plane on the basis of a light from the first plane, a second focusing system (G2) having two concave reflecting mirrors (CM21, CM22) for forming a second intermediate image of the first plane on the basis of a light coming from the first intermediate image, and a third focusing system (G3) for forming the final image of the first plane on the second plane on the basis of a light coming from the second intermediate image. The two concave reflecting mirrors have long spheroidal reflecting surfaces.

Description

Specification

Catadioptric imaging optical system, exposure apparatus, and method of manufacturing device

Technical field

The present invention relates to a catadioptric imaging optical system, an exposure apparatus, and a method of manufacturing a device, and in particular, an exposure apparatus used when manufacturing a microdevice such as a semiconductor element or a liquid crystal display element by photolithographic process. The present invention relates to a projection optical system suitable for

Background art

[0002] A photosensitive substrate (a wafer coated with a photoresist, a pattern image of a mask (or a reticle), a projection optical system, and the like, as in a photolithographic process for producing a semiconductor element, etc. An exposure apparatus for projecting and exposing onto a glass plate or the like is used. In the exposure apparatus, as the degree of integration of semiconductor elements and the like is improved, the resolution (resolution) required for the projection optical system is further increased. In order to satisfy the requirement for the resolution of the projection optical system, it is necessary to shorten the wavelength of the illumination light (exposure light) and to increase the image-side numerical aperture NA of the projection optical system. Therefore, there is known a liquid immersion technique for increasing the image-side numerical aperture by filling a medium such as a liquid having a high refractive index in the optical path between the projection optical system and the photosensitive substrate.

Generally, in a projection optical system having a large image-side numerical aperture, even if it is a drying system without being limited to the immersion system, it is possible to satisfy the Petzval condition to obtain the flatness of the image. Point of view of the ability to cope with any fine pattern for which it is desirable to adopt a catadioptric imaging optical system Forced field of view (in the case of an effective imaging area) does not include the optical axis! It is desirable to use an imaging optical system. Heretofore, as an off-axis type catadioptric imaging optical system suitable for an exposure apparatus, a three-time imaging type optical system including two reflecting mirrors has been proposed (see Patent Document 1).

Patent Document 1: International Publication No. WO 2005 Z069055 Pamphlet

Disclosure of the invention

Problem that invention tries to solve

In the conventional catadioptric imaging optical system disclosed in Patent Document 1, it is easy to secure a rectangular effective imaging area that makes it unnecessary to widely separate the off-axis field and the optical axis. . The However, in the prior art of Patent Document 1, in order to correct the spherical aberration of the pupil of the second imaging system, it is necessary to use a high-order aspheric surface as a reflecting mirror constituting the second imaging system, or 2) Use a reciprocating optical element (an optical element from which light rays enter and exit multiple times) between two reflecting mirrors in the imaging system! This is because, in the pupil plane of the second imaging system, a spherical aberration of the pupil that is too large to compensate for the first imaging system and the third imaging system occurs, and the telecentricity and distortion ) Is difficult to correct enough.

In general, surface measurement technology in processing a high order aspheric surface is complicated, and it is difficult to manufacture a reflecting mirror having a high order aspheric reflective surface with high accuracy. In addition, the reflective surface has a contribution to wavefront aberration of about 4 times and a contribution to the amount of flare light of about 13 times that of a refractive surface. Therefore, a configuration using a high-order aspheric surface as a reflecting surface is not preferable for optical lithography for achieving a resolving power of, for example, 100 nm or less. On the other hand, in the configuration in which the reciprocating optical element intervenes between the two reflecting mirrors in the second imaging system, the light is transmitted through the reciprocating optical element three times. Therefore, the optical system is caused by the absorption of the exposure light of the reciprocating optical element. The imaging performance of the lens tends to fluctuate greatly. In addition, if it is intended to secure a large exposure area (effective imaging area), it is easy to make the reciprocating optical element larger, which in turn tends to make the optical system larger.

The present invention has been made in view of the above problems, and has a high numerical aperture catadioptric aberration in which various aberrations are favorably corrected without using a high order aspheric reflecting surface and a reciprocating optical element. An object of the present invention is to provide an imaging optical system. The present invention also provides an exposure apparatus that can project and expose a fine pattern with high accuracy and high precision using a high numerical aperture catadioptric imaging optical system in which various aberrations are well corrected. To aim.

Means to solve the problem

[0008] In order to solve the above problems, in the first embodiment of the present invention, in a catadioptric imaging optical system that forms an image of a first surface on a second surface, based on light from the first surface. A first imaging system for forming a first intermediate image of the first surface and two concave reflecting mirrors, and a second intermediate image of the first surface is formed based on light from the first intermediate image And a third imaging system that forms a final image of the first surface on the second surface based on light from the second intermediate image, At least one concave reflector of the two concave reflectors provides a catadioptric imaging optical system characterized by having a long polar-shaped reflective surface. In addition, this The long prolate spheroid referred to in the invention is a spheroidal surface having a long axis on the optical axis, and the cone coefficient _K is 1 when the long prolate surface is expressed by the equation (b) described later. Ku there that Do and _Κ Ku 0.

In a second embodiment of the present invention, in the catadioptric imaging optical system for forming an image of the first surface on the second surface, the first of the first surface is formed based on the light from the first surface. A second imaging system having a first imaging system for forming an intermediate image, and two concave reflecting mirrors, and forming a second intermediate image of the first surface based on the light of the first intermediate image power; And a third imaging system that forms a final image of the first surface on the second surface based on light from the second intermediate image, and the two concave reflecting mirrors have the same shape as each other. A catadioptric imaging optical system characterized by having a reflective surface of

[0010] In the third embodiment of the present invention, in the off-axis catadioptric imaging optical system in which the image of the first surface is formed only on the area away from the optical axial force on the second surface, two curved surface shapes are provided. A catadioptric connection comprising: a reflecting mirror; and a plurality of dioptric optical elements, wherein at least one of the two curved reflecting mirrors has a long aspheric reflecting surface. Provide an image optical system. In a fourth aspect of the present invention, a method for projecting an image of the pattern on the photosensitive substrate set on the second surface based on light from the predetermined pattern set on the first surface is used. An exposure apparatus characterized by including the catadioptric imaging optical system of the first to third modes is provided. The fifth embodiment of the present invention includes an exposure step of exposing the photosensitive substrate to the predetermined pattern using the exposure apparatus of the fourth embodiment, and a developing step of developing the photosensitive substrate after the exposure step. Provide a method of manufacturing a device characterized by

Effect of the invention

According to a typical aspect of the present invention, in the three-time imaging type catadioptric imaging optical system, the second imaging system is configured of two concave reflecting mirrors having a long aspheric reflecting surface. It is done. The long concave spherical reflecting surface of the first concave reflecting mirror has one focal point positioned at the pupil position of the first imaging system and the other focal point positioned at the pupil position of the second imaging system. Is located in The long concave spherical reflecting surface of the second concave reflecting mirror has one focal point located at the pupil position of the third imaging system and the other focal point located at the pupil position of the second imaging system. Is located in Thus, according to the present invention, various aberrations including telecentricity and distortion are substantially suppressed by substantially suppressing the occurrence of spherical aberration of the pupil without using a high order aspheric reflecting surface and a reciprocating optical element. A well-corrected high numerical aperture catadioptric imaging system can be realized. Further, in the exposure apparatus of the present invention, a fine pattern can be projected and exposed faithfully and with high accuracy using a high numerical aperture catadioptric imaging optical system in which various aberrations are well corrected. The device can be manufactured with high precision.

Brief description of the drawings

FIG. 1 schematically shows a configuration of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a view showing the positional relationship between a stationary exposure area formed on a wafer and an optical axis.

FIG. 3 is a view showing a configuration between a boundary lens and a wafer in each embodiment.

FIG. 4 is a view showing a lens configuration of a projection optical system according to the first embodiment.

FIG. 5 is a view showing a lens configuration of a projection optical system according to a second embodiment.

FIG. 6 is a view showing a lens configuration of a projection optical system according to a third embodiment.

FIG. 7 is a diagram showing a lens configuration of a projection optical system according to a fourth embodiment.

FIG. 8 shows transverse aberration in the projection optical system of the first embodiment.

FIG. 9 shows transverse aberration in the projection optical system of the second embodiment.

FIG. 10 shows transverse aberration in the projection optical system of the third embodiment.

FIG. 11 is a diagram showing lateral aberration in the projection optical system of the fourth embodiment.

FIG. 12 is a diagram showing distortion in each example.

FIG. 13 is a diagram showing an error of telecentricity in each example.

FIG. 14 is a diagram schematically illustrating the operation and effects of the present embodiment.

FIG. 15 is a flowchart of a method for obtaining a semiconductor device.

FIG. 16 is a flowchart of a method for obtaining a liquid crystal display element.

Explanation of sign

R Reticule Nore

PL projection optics

Lb boundary lens

Lp plane parallel plate Lm Pure water (liquid)

W wafer

1 Illumination optics

14 Main control system

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described based on the attached drawings. FIG. 1 is a view schematically showing the configuration of an exposure apparatus according to an embodiment of the present invention. In FIG. 1, the X axis and the Y axis are set in a direction parallel to the wafer W, and the Z axis is set in a direction orthogonal to the wafer W. More specifically, the XY plane is set parallel to the horizontal plane, and the + Z axis is set upward along the vertical direction. As shown in FIG. 1, the exposure apparatus of this embodiment includes, for example, an illumination optical system 1 including an ArF excimer laser light source, which is an exposure light source, and configured as an optical integrator (field homogenizer), field stop, condenser lens and the like. Have.

The exposure light (exposure beam) IL which is also an ultraviolet pulse light power of wavelength 193 nm from which the light source power is also emitted passes through the illumination optical system 1 and illuminates the reticle (mask) R. A rectangular (slit-like) pattern area having a long side along the X direction and a short side along the Y direction of the entire pattern area is formed on the reticle R. Is illuminated. The light having passed through the reticle R is transferred to a predetermined exposure area on a wafer (photosensitive substrate) W coated with a photoresist through a projection optical system PL which is an immersion type catadioptric imaging optical system. Form a reticle pattern with reduced projection magnification. That is, on the wafer W, a rectangular stationary exposure having a long side along the X direction and a short side along the Y direction so as to optically correspond to the rectangular illumination area on the reticle R. A pattern image is formed in the area (effective exposure area; effective imaging area).

FIG. 2 is a view showing a positional relationship between a rectangular still exposure area (that is, an effective exposure area) formed on a wafer in the present embodiment and an optical axis. In this embodiment, as shown in FIG. 2, a circular area having a radius B centered on the optical axis AX (image circle) in the IF, a position away from the optical axis AX by an off-axis amount A in the Y direction. A rectangular effective exposure area ER having a desired size is set. Here, X of the effective exposure area ER The length in the direction is LX, and the length in the Y direction is LY. Therefore, although not shown, on the reticle R, the effective exposure area ER is located at a distance from the optical axis AX in the Y direction by a distance corresponding to the off-axis amount A corresponding to the rectangular effective exposure area ER. A rectangular illumination area (that is, an effective illumination area) having a corresponding size and shape is formed.

Reticle R is held on reticle stage RST in parallel to the XY plane, and reticle stage RST incorporates a mechanism for finely moving reticle R in the X direction, Y direction, and rotational direction. In reticle stage RST, the positions in the X direction, Y direction and rotational direction are measured and controlled in real time by a reticle laser interferometer (not shown). Wafer W is fixed parallel to the XY plane on Z stage 9 via a wafer holder (not shown). The Z stage 9 is fixed on an XY stage 10 which moves along an XY plane substantially parallel to the image plane of the projection optical system PL, and the focus position (position in the Z direction) of the wafer W and Control the tilt angle. The Z stage 9 is measured and controlled in real time in the X direction, Y direction and rotational direction by a wafer laser interferometer 13 using a movable mirror 12 provided on the Z stage 9.

The XY stage 10 is mounted on the base 11, and controls the X direction, the Y direction, and the rotation direction of the wafer W. On the other hand, the main control system 14 provided in the exposure apparatus of the present embodiment is based on the measurement values measured by the reticle laser interferometer, and the positions of the reticle R in the X direction, Y direction and rotation direction. Make adjustments. That is, the main control system 14 transmits a control signal to a mechanism incorporated in the reticle stage RST and moves the reticle stage RST finely to adjust the position of the reticle R. Further, the main control system 14 aligns the surface on the wafer W with the image plane of the projection optical system PL by the autofocus method and the auto leveling method, so the focus position (position in the Z direction) and tilt angle of the wafer W Adjust the That is, the main control system 14 transmits a control signal to the wafer stage drive system 15, and adjusts the focus position and the inclination angle of the wafer W by driving the Z stage 9 by the Ueno, stage drive system 15. .

Further, the main control system 14 adjusts the position of the wafer W in the X direction, the Y direction, and the rotational direction based on the measurement values measured by the wafer laser interferometer 13. That is, the main control system 14 A control signal is sent to the wafer stage drive system 15 and the XY stage 10 is driven by the wafer stage drive system 15 to adjust the position of the wafer W in the X direction, Y direction and rotation direction. At the time of exposure, the main control system 14 transmits a control signal to the mechanism incorporated in the reticle stage RST, and transmits a control signal to the wafer stage drive system 15, and the speed ratio according to the projection magnification of the projection optical system PL. At the same time, the reticle stage RST and the XY stage 10 are driven, and the pattern image of the reticle R is projected and exposed onto a predetermined shot area on the wafer W. After that, the main control system 14 transmits a control signal to the wafer stage drive system 15 to drive the XY stage 10 by means of the stage drive system 15 to move another shot area on the wafer W to the exposure position. Step move.

In this manner, the operation of scanning and exposing the pattern image of the reticle R onto the wafer W is repeated by the step 'and' scan method. That is, in the present embodiment, while controlling the position of reticle R and wafer W using wafer stage drive system 15 and wafer laser interferometer 13 etc., the short side direction of the rectangular static exposure area and static illumination area is detected. The reticle stage RST and the XY stage 10 along the Y direction are moved (scanned) synchronously with the reticle scale and the wafer W, so that the long side of the still exposure area on the wafer W A reticle pattern is scan-exposed to a region equal to LX and having a width and a length corresponding to the scanning amount (moving amount) of the wafer W.

FIG. 3 is a view schematically showing a configuration between the boundary lens and the wafer in each example of the present embodiment. In the first embodiment, the second embodiment, the third embodiment and the fourth embodiment of the present embodiment, as shown in FIG. 3A, the light path between the boundary lens Lb and the wafer W is liquid Lm. be satisfied. In the third example of this embodiment, as shown in FIG. 3B, the optical path between the plane parallel plate Lp and the wafer W and the optical path between the boundary lens Lb and the plane parallel plate Lp are liquid L m Is filled with In the third embodiment, as shown in FIG. 1, the pure water as the liquid Lm is circulated in the light path between the plane parallel plate Lp and the wafer W by using the first water supply and drainage mechanism 21, and the second water supply and drainage mechanism. 22 is used to circulate pure water as liquid Lm in the optical path between the boundary lens Lb and the plane parallel plate Lp. In the first embodiment, the second embodiment, the third embodiment and the fourth embodiment, the liquid supply and drainage mechanism (not shown) is used to set the liquid in the optical path between the boundary lens Lb and Ueno and W. Circulate pure water as Lm! In each example of the present embodiment, the aspheric surface has a height in the direction perpendicular to the optical axis as y, and the tangential force at the vertex of the aspheric surface is the optical axis up to the position on the aspheric surface at the height y. Letting z be the distance (sag amount) along r, r be the radius of curvature of the apex, _K be the conical coefficient, and C be the aspheric coefficient of order η, it is expressed by the following equation (b). In Tables (1) to (4) to be described later, an optical surface formed in an aspheric shape is given an * mark on the right side of the surface number.

z = (y Vr) / [l + {l-(l + _K )-y ² / r ² } ^{1 2} ] + C-y ⁴ + C-y ⁶

4 6

+ CV + C-y ¹⁰ + C-y ¹² + C ' _y "+ C-y ¹⁶ (b)

8 10 12 14 16

Further, in each example of the present embodiment, the projection optical system PL is a first imaging system G1 that forms a first intermediate image of the pattern of the reticle R disposed on the object surface (first surface). And a second imaging system G2 for forming a second intermediate image (an image of the first intermediate image and a secondary image of a reticle pattern) of the reticle pattern based on the light of the first intermediate image, and the second imaging system G2 And a third imaging system G3 for forming a final image (a reduced image of the reticle pattern) of the reticle pattern on the wafer W disposed on the image plane (the second surface) based on the light of intermediate image power. . The first imaging system G1 and the third imaging system G3 are both dioptric systems (optical systems that do not include a reflecting mirror), and the second imaging system G2 is a catoptric system in which only two concave reflecting mirrors can also act. . In the projection optical system PL of each embodiment, the first imaging system Gl, the second imaging system G2, and the third imaging system G3 extend along one optical axis AX linearly extending along the vertical direction. Each is arranged. In each embodiment, the projection optical system PL is substantially telecentric on both the object side and the image side !.

First Embodiment

FIG. 4 is a view showing a lens configuration of a projection optical system according to the first example of the present embodiment. In the projection optical system PL which is applied to the first embodiment, the first imaging system G1 is composed of a plane parallel plate P1 and ten lenses L11 to L110 in order on the reticle side force. The second imaging system G2 includes, in order from the light incident side, a first concave reflecting mirror CM21 having a long aspheric concave surface directed to the incident side (reticle side), and a long aspheric surface on the incident side (wafer side) And a second concave reflector CM22 with the concave surface facing the second concave mirror CM22. More specifically, the long concave spherical reflecting surface of the first concave reflecting mirror CM21 and the long concave spherical reflecting surface of the second concave reflecting mirror CM22 are part of an elliptical surface having a major axis on the optical axis AX. Each is configured. Also, the first concave reflector C The M 21 and the second concave reflecting mirror CM 22 have reflecting surfaces of the same shape. The first concave reflecting mirror CM21 is disposed such that one focal point is located at the pupil position of the first imaging system G1 and the other focal point is located at the pupil position of the second imaging system G2. The second concave reflecting mirror CM22 is disposed such that one focal point is located at the pupil position of the third imaging system G3 and the other focal point is located at the pupil position of the second imaging system G2, .

The third imaging system G3 is also configured by lenses L31 to L312 and a plano-convex lens L313 (boundary lens Lb) having a flat surface facing the wafer side in order on the reticle side (that is, the light incident side) force! Follow In the first embodiment, a variable aperture stop AS (not shown) for changing the numerical aperture of the projection optical system PL is provided between the lenses L39 and L310. Also, in the optical path between the boundary lens Lb and the wafer W, pure water having a refractive index of 1.435876 for ArF excimer laser light (center wavelength E = 19 3. 306 nm) which is the use light (exposure light) (Lm) is satisfied. In addition, all light transmitting members including the boundary lens Lb are made of quartz (SiO 2) having a refractive index of 1.503261 with respect to the central wavelength of the used light.

2

Table 1 below shows values of specifications of the projection optical system PL that are the key to the first example. In Table (1), λ is the central wavelength of the exposure light, j8 is the size of the projection magnification (imaging magnification of the whole system), Ν A is the image side (wafer side) numerical aperture, and B is Ueno. The radius of the image circle IF (maximum image height) on W, A is the off-axis amount of the effective exposure area ER, and LX is the dimension along the X direction of the effective exposure area ER (dimension of the long side) LY represents the dimension (dimension of the short side) of the effective exposure region ER along the Y direction. The surface number indicates the order of the reticle side force along the path of the light beam from the reticle plane, which is the object plane (first plane), to the wafer plane, which is the image plane (second plane). The radius of curvature of the surface (in the case of an aspheric surface, the vertex radius of curvature: mm), d indicates the on-axis spacing of each surface, ie, the surface spacing (mm), and n indicates the refractive index for the central wavelength. In addition, the notation in Table (1) is the same as in the following Tables (2) to (4)

Table (1)

(Major specifications)

= 193. 306 nm

β = 1/4 n // v: .ss 900 ifcl £ O osiuAV

/ O osiz-oozAV

690 0690 inch τ τ ·

() no size

ΐ 69 69 00000 OS Ζ S ·

SS0 寸 9ΐ. Εεο εss *,

ΐεΐ size 3ΐε,

Dimension 3 ·

(3 ΐεΐ 98999 ΐε ΖΓΖΙ,

(39 inch size

Ε 9ε *

() εΊ

() Ε ε π∞ size 06 Ί 3 ·

0002η 06εε ο Dimensions.

(36 sosss ΐ r

0 = ^¾ -Bsz

0 = o

0IXZ99SI "g 0IX0S8 ^ I · D

OT

12-'9 = O

0 = ^¾ -B9Z

91 n

0 = O 0 = O 0 =-D 0 = O 0 = O 0 = O 0 = O

t_0Tx6 ^ i9-= Ί3⁄4α εζ

91

0 = o n

εε- 0IXI9Z ^ Z 'Ζ 92 OIXO ^ OZO' Shi-

OT

\ z-oixxeszo O _ZI _0 lX 98 ^ Sg 'Z-

01X009X9 P = D ₈ _OXXS 9 ^ IO '9

91 ε ε θ ζζ ε ε ζ = o

82- 0XX968 II D 0 IX S 69 S 9 'Z = O

01

02- 0IX8S0S8 Έ 91 OI LZ LQ Έ = ⁸ pieces

0IX08Z9S ₈ _0IX 90002 '8 = One

n

oixtoo · ε = o £ 2-0ΙΧ ^ 986Ζ 'ε-= ο

61 01 X 888 99 91 0 ΙΧΖΤΤ 96 '9 = 3

01X09620 '6 D, _0 ΙΧ 96 ^ 9-= ο

0 =: 厘 6 (— 厘翁 ^) (3⁄4, /)

(^ Ί) 9 83 ε ^ · ΐ 00000 · IS IS (^ 1-£ 1 £ Ϊ 93 ε 09 3 · ΐ 86 ΐ ε · 6 8 £ 068 '£ 6 09

00000 · ΐ

ll.Sif / 900Zdf / X3d 0H980 request Z ΟΛ \ O

〇 l o C 2.6 x = I 10. 298 ^ 10 C 3.3 633 XX =

C = -2.54603 X 10

16

49: κ = 0

C = 5.39853X10- ⁸ C = 6.72332X10- ¹²

4 6

^{C = - 7.01770X10- 16 C = 1.02255X10-} 19

8 10

^{C = - 9.46223X10- 24 C = 6.48610} X 10- 28

12 14

C = -1.97332X10- ³²

16

Second Embodiment

FIG. 5 is a view showing a lens configuration of a projection optical system according to a second example of the present embodiment. The projection optical system PL of the second embodiment has a configuration similar to that of the projection optical system of the first embodiment. The first imaging system G1 is composed of a plane parallel plate P1 and nine lenses L11 to L19. The points are different from the first embodiment. As in the first embodiment, the second embodiment is also provided between the variable aperture stop AS (not shown) force lens L39 and L310 for changing the numerical aperture of the projection optical system PL. In addition, the optical path between the boundary lens Lb and the wafer W is filled with pure water (Lm) having a refractive index of 1.435876 with respect to the central wavelength (λ = 193.306 nm) of the used light. In addition, all the light transmitting members including the boundary lens Lb are made of quartz having a refractive index of 1.5603261 with respect to the central wavelength of the used light. Table 2 below summarizes values of specifications of the projection optical system PL that are the key to the second example.

Table (2)

(Major specifications)

= 193.306 nm

β = 1/4

ΝΑ = 1.3

Β = 15.3 mm

A = 3 mm

LX = 26 mm

LY = 5 mm

(Optical member specifications)

Surface number rdn Optical member //: O ϊϊ / 3⁄4ε9002τ1 £ osi-oozAV

S) Ϊ 00000 OS Λ / ヽ Ζ

Ζ 6 *

Moth

Six

600 OS

ΐεεΐε9ζ ·

0002η εεε *, εεΐ, C. 898 l l. I. 212 610 x X = I

C9.6 1813 3.618 l0 Xx = l

c = =

l 1. 1. 686 C x = ^ 34: κ = 0

c 8. 08755X10 "

16

Pure water (Lm) with a refractive index of 1.435876 is filled against the heart wavelength (λ = 193. 306 nm). Further, all light transmitting members including the boundary lens Lb and the plane parallel plate Lp are made of quartz having a refractive index of 1.5603261 with respect to the central wavelength of the light used. Table 3 below shows values of specifications of the projection optical system PL that are the key to the third example.

Table (3)

(Major specifications)

= 193. 306 nm

β = 1/4

ΝΑ = 1.3

Β = 15. 3 mm

A = 3 mm

LX = 26 mm

LY = 5 mm

(Optical member specifications)

Surface number r d n Optical member

(Reticle plane) 60.59272

1 oo 8.00000 1, .5603261 (P1)

2 oo 3.00000

3 350.00000 25.01025 1.5603261 (L11)

4-1224.92925 1.00000

5 206.91963 33.55065 1.5603261 (L12)

6 -4382.64940 4.05890

7 128.14708 51.26364 1.5603261 (L13)

8-19802.221291 10.73486

9 *-10000.00000 21.70324 1.5603261 (L14)

10 227.01998 9.85859

11 536.14092 30.62633 1.5603261 (L15)

12-180.47868 31.92390

/ O osiz-oozAV words) Ϊ 92 ε 09 ΐ 3 ·

S6ss size ε size ΐrι

Ε 92 ΐ 09 ΐ 66000 ε 6 § 9 ΐ 33 ·,.

3⁄4) ΐ 92 ο ΐ ε Ί £ Ί 3. 言) Ϊ 92ε 09 ΐ S dimension 3 S S ·

S9O9 OS SZSI

(5 yo Ϊ 92ε09 ΐ 3 ·,

ο

σ) ε Ϊ 92 ε 09 ΐ SO dimension 699 S Ί 3 S ..

SO dimension εεεssS * ·) 3 ΐ 92 ο ΐ ε 3.

6 pieces 6 pieces 3 pieces

() 9 Ϊ 92 ΐ 09 Ί 3 3 3 Ϊ 92 ΐ 09 ΐ ΐ 92 ΐ 3 ·

0002η

() Hino

() 41 3334.64266 45.38994 1.5603261 L39

C C =-4. 53768 X ^10-35

c -24 -28

5. 78534 X 10 C = 3. 15579 X 10

12

The optical path to W is filled with pure water (Lm) having a refractive index of 1.435876 for the wavelength (λ = 193. 306 nm) in the used light. Further, all the light transmitting members including the boundary lens Lb are made of quartz having a refractive index of 1.5603261 with respect to the central wavelength of the used light. In the following Table (4), values of various items of the projection optical system PL, which are the components of the fourth embodiment, are listed.

Table (4)

(Major specifications)

= 193. 306 nm

β = 1/4

ΝΑ = 1.3

Β = 15. 5 mm

A = 3 mm

LX = 26 mm

LY = 5. 4 mm

(Optical member specifications)

Surface number r d n Optical member

(Reticle plane) 50.00000

1 oo 8.00000 1.5603261 (P1)

2 oo 3.00000

3 350.00000 26.46669 1.5603261 (L11)

4-65.5 3379 1.00000

5 173.21612 35.96742 1.5603261 (L12)

6 -4461.333635 17.43708

7 429.14439 29.48354 1.5603261 (L13)

8-275.94579 1.00000

9 *-10000.00000 12.00000 1.5603261 (L14)

10 196.20422 8.94774

11 258.27992 39.92164 1.5603261 (L15) //: / O ϊϊ / 3⁄4ε9002τ1 £ osiz-oozAV

0002η Οΐΐΐ- · ·

(38 ΐ 92 寸 006 006 3 3 Ζ.,

(36 ΐ 92 ΐ size 606023 ...

ΐεΐ,

(3 ΐ 92 ο ΐ ε ΐ 3.,

() 93 ΐ 92 ΐ 3.

(39 ΐ 92 ΐ 3.

s 寸 ^ εΐ ·

() Ε ε Ϊ 92 ε 09 ΐΊ 3.

() Ϊ́ ε ΐ 92 ΐ 09π6επεΊ 3 ζ. ·

() 63 ΐ 92 ΐ 3. =

Yes

^ ~

8

C C =

9102.1767 CX = l 772 07721212.053 ^ x CX = 45: K = 0

^{C = 5.41768X10- 9 C = - 1.} 25187X10

Four

^{C = -2.46535X10- 17 C = 2 91835X10-} .:

8 10

^{C = -1. 30286X10- 21 C =} 2.86312X10

12

C = -2. 57739X10- ³¹

16

47: K = 0

^{C = 5. 72850X10- 8 C =} 5. 35881X10

Four

^{. C = -3 99564X10- 16 C =} 4 99873X10-.:

8 10

^{C = -2. 75405X10- 2 C =} 1. 34776X10

12

C = -6.81632X10- ³ '

16

FIG. 8 shows transverse aberration in the projection optical system of the first embodiment. FIG. 9 is a diagram showing lateral aberration in the projection optical system of the second embodiment. FIG. 10 is a diagram showing lateral aberration in the projection optical system of the third embodiment. FIG. 11 shows transverse aberration in the projection optical system of the fourth embodiment. In the aberration diagrams of FIG. 8 to FIG. 11, Y indicates the image height. FIG. 12 is a diagram showing distortion (distortion aberration; displacement amount from an ideal image position) in the projection optical system of each example. FIG. 13 is a diagram showing an error of telecentricity (incident angle of a main light beam to the wafer W when the reticle side is ideally telecentric on the reticle side) in the projection optical system of each example. In FIG. 12, the vertical axis is the displacement amount (nm) of the image, and in FIG. 13, the vertical axis is the incident angle of the chief ray (rad: radian).

12 and 13, the horizontal axis is the image height (mm), the solid line indicates the first embodiment, the alternate long and short dashed line indicates the second embodiment, and the broken line indicates the third embodiment. Referring to FIGS. 8 to 13, in each embodiment, a very large image-side numerical aperture (NA = 1.3) and a relatively large static exposure area ER (26 mm × 5 mm or 26 mm × 5.4 mm) are secured. It can be seen that aberrations, including telecentricity and distortion, are well corrected for excimer laser light with a wavelength of 193. 306 nm. In FIGS. 12 and 13, force that omits the display of the error of distortion and telecentricity in the fourth example also in the fourth example as in the other examples, various aberrations including telecentricity and distortion. Make sure that is well corrected doing.

As described above, in each example of the present embodiment, a high image-side numerical aperture of 1.3 is secured for ArF excimer laser light with a center wavelength of 193.306 nm, and 26 mm × 5 mm Can secure a 26 mm x 5.4 mm rectangular effective exposure area (static exposure area) ER, for example, scan and expose a circuit pattern with high resolution in a 26 mm x 33 mm rectangular exposure area. be able to. Further, in each example of the present embodiment, a catadioptric imaging optical system is adopted, so that the Petzval condition is almost satisfied despite the large image side numerical aperture to obtain the flatness of the image. Can. Furthermore, since the effective visual field area (effective illumination area) and the effective projection area (effective exposure area ER) use an imaging optical system with an off-axis field of view type that does not include the optical axis, Can be secured.

In particular, in each example of the present embodiment, one focal point of the long concave spherical reflecting surface of the first concave reflecting mirror CM21 is located at the pupil position of the first imaging system G1, and the other focal point is The second imaging system G2 is located at the pupil position, and the focal point of one of the long aspheric reflecting surfaces of the second concave reflecting mirror CM22 is located at the pupil position of the third imaging system G3 and the other The focal point is located at the pupil position of the second imaging system G2. Therefore, as shown in FIG. 14 (a), a ray from point P1 on the optical axis of the pupil plane of the first imaging system G1 is reflected by the long aspheric surface of the first concave reflecting mirror CM21. The light is condensed at a point P2 on the optical axis of the pupil plane of the second imaging system G2. Although illustration is omitted, a ray from a point P2 on the optical axis of the pupil plane of the second imaging system G2 is reflected by the long concave spherical reflecting surface of the second concave reflecting mirror CM22. Focus on a point on the optical axis of the pupil plane of the imaging system G3. As a result, spherical aberration of the pupil substantially does not occur at the pupil plane of the second imaging system G2.

On the other hand, as shown in FIG. 14 (b), in the configuration using the concave reflecting mirror CM having a spherical reflecting surface, the point force on the optical axis of the pupil plane of the first imaging system is A ray of light generates a relatively large pupil spherical surface aberration that can not be condensed at a point on the optical axis of the pupil plane of the second imaging system through the concave reflecting mirror CM. Therefore, in the prior art, it is preferable to use a high-order aspheric surface (an aspheric surface having a high-order term (2nd or higher) of aspheric coefficient) for the reflecting mirror constituting the second imaging system or It was necessary to use a reciprocating optical element between the two reflectors. In each example of the present embodiment, a pair of long aspheric spherical reflecting surfaces (high order terms of aspheric coefficients (second The introduction of aspheric surfaces (top) does not substantially reduce the occurrence of spherical aberration of the pupil without using reflecting surfaces of higher order aspheric shapes and reciprocating optical elements, thereby achieving telecentricity and distortion. It is possible to realize a high numerical aperture projection optical system in which various aberrations including those are well corrected.

In the surface measurement of the concave reflecting mirrors CM21 and CM22 having a long-aspheric spherical reflecting surface, it is possible to use a spherical surface measurement technique using two focal points. That is, as shown in FIG. 14 (c), which is a relatively complex aspheric measurement technique using a null element etc., it is based on a relatively simple spherical measurement technique using Fizeau optical system 100 and folded spherical reflector 101. Thus, concave reflecting mirrors CM21 and CM22 having long spherical surface-like reflecting surfaces can be manufactured with high accuracy. In particular, in the first to third examples of the present embodiment, since the first concave reflecting mirror CM21 and the second concave reflecting mirror CM22 have reflecting surfaces of the same shape, manufacturing of the concave reflecting mirrors CM21 and CM22 It is possible to reduce the cost and hence the manufacturing cost of the optical system.

On the other hand, in the fourth example of the present embodiment, the first concave reflecting mirror CM21 and the second concave reflecting mirror CM22 have reflecting surfaces in the form of long aspheric surfaces different from each other. However, both the first concave reflecting mirror CM21 and the second concave reflecting mirror CM22 have an opening for transmitting the imaging light flux, and an effective reflection corresponding to a part of a curved surface substantially rotationally symmetric with respect to the optical axis AX. It has a face. As a result, the first concave reflecting mirror CM21 and the second concave reflecting mirror CM22 are supported at a plurality of positions approximately at a distance from the optical axis AX, for example, at a plurality of substantially rotationally symmetric positions with respect to the optical axis AX. Can be used to easily and precisely assemble and adjust the optical system using conventional techniques. In the fourth embodiment, although both the first concave reflecting mirror CM21 and the second concave reflecting mirror CM22 have openings for passing the imaging light beam, the first concave reflecting mirror is not limited to this. A modification is also possible in which one of the CM 21 and the second concave reflecting mirror CM 22 has an opening.

By the way, in the present embodiment, the long aspheric spherical reflecting surface of the concave reflecting mirror CM21, CM22 has a high-order term (C 1, y 2) including the aspheric coefficient C from the above equation (b) representing an aspheric surface. It is expressed by the following equation (a) from which ⁿ ) is removed, and it is preferable that the conic coefficient _K satisfies the following condition (1). z = (y Vr) Z [l + {1-(l +)) · y / r ² } ^{1 2} ] (a)

-0. 75 <K <-0. 25 (1)

If the upper limit value of the conditional expression (1) is exceeded, the two focal positions of the long aspheric reflective surface come too close to each other, and the long aspheric reflective surface approaches a spherical surface, so the first imaging The exit pupil position of the system or the entrance pupil position of the third imaging system needs to approach the second imaging system. As a result, the angle between the peripheral chief ray and the optical axis becomes large, which causes the enlargement of the concave reflecting mirror, which is not preferable. If the lower limit value of conditional expression (1) is exceeded, the two focal positions of the long aspheric reflective surface will be too far apart, and the long aspheric reflective surface will approach the paraboloid, so The exit pupil position of the image system or the entrance pupil position of the third imaging system is far from the second imaging system. As a result, it is necessary to increase the refractive power of the second imaging system side field lens group in the first imaging system and the third imaging system, making it difficult to correct the spherical aberration of the pupil, As a result, the telecentricity and distortion can not be compatible and corrected, which is preferable. In order to obtain a better effect of the present invention, it is preferable to set the upper limit value of conditional expression (1) to −0.35 and the lower limit value to 0.65.

In the above embodiment, although both the first concave reflecting mirror CM21 and the second concave reflecting mirror CM22 have the long aspheric spherical reflecting surface, any one of the concave surfaces is not limited thereto. The effect of the present invention can be obtained by making the reflecting surface of the reflecting mirror into a long, aspheric surface. In the first to third examples of the above-described embodiment, the first concave reflecting mirror CM21 and the second concave reflecting mirror CM22 have reflecting surfaces of the same shape as each other, but the present invention is limited to this. If the reflecting surface of any one concave reflecting mirror has a long aspheric surface, the effect of the present invention can be obtained even when the two concave reflecting mirrors have reflecting surfaces of different shapes. Incidentally, in the fourth example of the above-mentioned embodiment, the two concave reflecting mirrors have reflecting surfaces in the form of long aspheric surfaces different from each other. However, as described above, in the configuration in which the first concave reflecting mirror CM21 and the second concave reflecting mirror CM22 have reflecting surfaces of the same shape, the manufacturing cost of the concave reflecting mirror can be reduced. According to this point of view, for example, in a three-time imaging type catadioptric imaging optical system, two concave reflecting mirrors having the same shape reflecting surfaces in the second imaging system are disposed. It is important to do.

In the above-described embodiment, the first imaging system G1 and the third imaging system G3 include reflecting mirrors. Although the optical system is configured as a non-refractive type optical system, various modifications can be made to the configuration of the first imaging system G1 and the third imaging system G3 that can not be limited to this. In the above-described embodiment, the second imaging system G2 is configured by only two concave reflecting mirrors, but various modifications may be made to the configuration of the second imaging system G2 which is not limited to this. It is possible.

Further, although the present invention is applied to the immersion type catadioptric imaging optical system in the above-described embodiment, the immersion liquid is used in the image side area which is not limited to this. The present invention can be similarly applied to a non-dry-type catadioptric imaging optical system. Further, although the present invention is applied to the off-axis type catadioptric imaging optical system in which the image is formed only in the area away from the optical axis in the above-described embodiment, the present invention is limited thereto. The present invention can be similarly applied to a catadioptric imaging optical system that forms an image in a region including an optical axis which is not far away. Further, in the above embodiment, the present invention is applied to the three-time imaging type catadioptric imaging optical system, but the present invention is not limited to this. The present invention can be similarly applied to an off-axis type catadioptric imaging optical system provided with a refractive optical element.

In the exposure apparatus of the above-described embodiment, the reticle (mask) is illuminated by the illumination device (illumination step), and the transfer pattern formed on the mask is exposed on the photosensitive substrate using the projection optical system. By the (exposure step), microdevices (semiconductor elements, imaging elements, liquid crystal display elements, thin film magnetic heads, etc.) can be manufactured. Hereinafter, the flowchart of FIG. 15 is shown as an example of a method for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a wafer as a photosensitive substrate or the like using the exposure apparatus of the present embodiment. Refer to the description.

First, in step 301 of FIG. 15, a metal film is vapor-deposited on one lot of wafers. In the next step 302, photoresist is applied on the metal film on the one lot wafer. Thereafter, in step 303, using the exposure apparatus of this embodiment, the image of the pattern on the mask is sequentially exposed and transferred to each shot area on the wafer of one lot through the projection optical system. Thereafter, in step 304, after development of the photoresist on the wafer of one lot is performed, in step 305, the resist on the wafer of one lot is registered. The circuit pattern force corresponding to the pattern on the mask is formed in each shot area on each wafer by performing etching using the pattern as a mask.

Thereafter, by further forming the circuit pattern of the upper layer and the like, a device such as a semiconductor element is manufactured. According to the above-described semiconductor device manufacturing method, a semiconductor device having a very fine circuit pattern can be obtained with high throughput. In steps 301 to 305, metal is vapor-deposited on the wafer, a resist is applied on the metal film, and the force of performing each of the exposure, development, and etching steps is performed on the wafer prior to these steps. It is needless to say that after forming a silicon oxide film, a resist may be coated on the silicon oxide film, and then each process such as exposure, development and etching may be performed.

In addition, in the exposure apparatus of the present embodiment, a liquid crystal display device as a microdevice can also be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). . An example of the method will be described below with reference to the flowchart of FIG. In FIG. 16, in the pattern forming step 401, a so-called photolithographic process is performed in which a mask pattern is transferred and exposed onto a photosensitive substrate (such as a glass substrate coated with a resist) using the exposure apparatus of this embodiment. Ru. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate is subjected to steps such as a developing step, an etching step and a resist removing step to form a predetermined pattern on the substrate, and the process proceeds to the next color filter forming step 402. .

Next, in the color filter formation step 402, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix, or R, G, A color filter is formed by arranging a plurality of B stripe filters in the direction of horizontal scanning lines. Then, after the color filter formation step 402, a cell assembly step 403 is performed. In the cell assembling step 403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern forming step 401, the color filter obtained in the color filter forming step 402, and the like.

In the cell assembling step 403, for example, the predetermined pattern obtained in the pattern forming step 401 is A liquid crystal is injected between a substrate having a turn and the color filter obtained in the color filter forming step 402 to manufacture a liquid crystal panel (liquid crystal cell). Thereafter, in a module assembling step 404, components such as an electric circuit for performing a display operation of the assembled liquid crystal panel (liquid crystal cell), a backlight and the like are attached to complete a liquid crystal display element. According to the above-described method of manufacturing a liquid crystal display device, a liquid crystal display device having a very fine circuit pattern can be obtained with high throughput.

In the above-described embodiment, the force using the ArF excimer laser light source is not limited to this, and another appropriate light source such as an F 2 laser light source can also be used.

2

However, when F laser light is used as the exposure light, F laser light can be transmitted as the liquid.

twenty two

For example, a fluorinated liquid such as fluorinated oil or perfluoropolyether (PFPE) is used. In the above-described embodiment, the present invention is applied to the projection optical system mounted on the exposure apparatus, but the present invention is not limited to this, and the present invention is not limited to this. The invention can be applied.

Claims

The scope of the claims

[1] In a catadioptric imaging optical system for forming an image of a first surface on a second surface,

A first imaging system for forming a first intermediate image of the first surface based on the light from the first surface; and two concave reflecting mirrors, the first imaging system based on the light of the first intermediate image force A second imaging system that forms a second intermediate image of the first surface;

And a third imaging system that forms a final image of the first surface on the second surface based on light from the second intermediate image,

A catadioptric imaging optical system characterized in that at least one concave reflector of the two concave reflectors has a long aspheric reflective surface.

[2] One of the focal points of the long aspheric reflecting surface is located at or near the pupil position of the first imaging system or the third imaging system, and the other focal point is the second imaging system The catadioptric imaging optical system according to claim 1, wherein the catoptric lens is disposed so as to be located at or near a pupil position of the lens.

[3] The catadioptric imaging optical system according to Claim 1 or 2, wherein the two concave reflecting mirrors both have a long aspheric spherical reflecting surface.

[4] The two concave reflectors have reflecting surfaces of the same shape.

The catadioptric imaging optical system according to any one of 1 to 3.

[5] In the catadioptric imaging optical system for forming an image of the first surface on the second surface,

A catadioptric imaging optical system characterized in that the two concave reflectors have reflecting surfaces of the same shape.

[6] The catadioptric imaging optical system according to Claim 5, wherein the two concave reflecting mirrors have long spherical-shaped reflecting surfaces.

[7] The first imaging system and the third imaging system are refractive optical systems that do not include a reflecting mirror. The catadioptric imaging optical system according to any one of claims 1 to 6, wherein

8. The catadioptric imaging optical system according to any one of claims 1 to 7, wherein the second imaging system is constituted only by the two concave reflecting mirrors.

[9] An off-axis type catadioptric imaging optical system in which the image of the first surface is formed only on the area away from the optical axis on the second surface.

Comprising two curved reflectors and a plurality of refractive optical elements,

A catadioptric imaging optical system characterized in that at least one curved reflector of the two curved reflectors has a long aspheric reflective surface.

10. The catadioptric imaging optical system according to claim 9, wherein the two curved reflecting mirrors and the plurality of dioptric optical elements are disposed coaxially with the optical axis. .

[11] The two curved reflecting mirrors are concave reflecting mirrors.

The catadioptric imaging optical system described in 0.

[12] The catadioptric imaging optical system according to Claim 11, wherein the two concave reflecting mirrors both have a long aspheric spherical reflecting surface.

[13] The catadioptric imaging optical system according to any one of claims 9 to 12, wherein the two curved reflecting mirrors have reflecting surfaces of the same shape.

[14] The long aspheric reflecting surface has a height in the direction perpendicular to the optical axis as y, and the tangential force at the apex of the reflecting surface is at the optical axis up to the position on the reflecting surface at the height y. Assuming that the distance along the distance (sag amount) is z, the vertex radius of curvature is _K, and the conical coefficient is _K , z is represented by the following equation (a): z = (y Vr) Z [l + {1-(l + κ) · Y / r ² } ^{1 2} ] (a)

The catadioptric imaging according to any one of claims 1 to 4 and any one of claims 6 to 13, wherein the conical coefficient κ satisfies the condition of -0.75 <κ <0.25. Optical system.

[15] At least one concave reflector of the two concave reflectors has an opening for passing an imaging light beam, and is supported at a plurality of positions approximately at the same distance from the optical axis. The catadioptric imaging optical system according to any one of claims 1 to 14, characterized in that:

[16] The reflector according to claim 15, characterized in that at least one concave reflector of the two concave reflectors is supported at a plurality of positions substantially rotationally symmetric with respect to the optical axis. Refractive imaging optics.

[17] At least one concave reflector of the two concave reflectors has an effective reflection surface corresponding to a part of a curved surface substantially rotationally symmetric with respect to the optical axis. The catadioptric imaging optical system of any one of the above.

[18] Any one of claims 1 to 17 for projecting an image of the pattern on the photosensitive substrate set on the second surface based on light of a predetermined pattern force set on the first surface. An exposure apparatus comprising the catadioptric imaging optical system according to item 1.

[19] An exposure step of exposing the predetermined pattern to the photosensitive substrate using the exposure apparatus according to claim 18.

And d. Developing the photosensitive substrate that has undergone the exposing step.